Biomass co-gasification with coal:: The process benefit due to positive synergistic effects

Investigation of co-gasification of biomass-coal blends in oxygen-containing atmosphere was carried out in a pressurized fluidized bed gasifier. Different biomass materials including wood and energy crop were used in the study, whereas the coal used was in bituminous rank from UK. The gasifier used was a Laboratory Development Unit (LDU) with an inner diameter of 144 nun. The operation temperature and pressure were varied in the investigation. The research was part of the European Union's Joule III clean coal technology programme. The study was focused on possible synergies in the thermochemical treatment of the fuel blends. The char formed was examined. The tar produced in the process was analyzed. The environmentally concerned nitrogen compounds emitted from the process were detected. Interesting synergies were observed in the experimental study. The blends of the fuels and their char formed in situ demonstrated unexpected high reaction rate of gasification under the studied conditions. The yield of char diminished and consequently gas production was promoted. Furthermore, both the formation of tar and nitrogen compounds seemed also affected synergically in co-gasification of the fuel blends. The yields of tar and ammonia were lower than expected.